1. Field of the Invention
The present invention concerns devices for detecting obstacles, more particularly intended to equip motor vehicles, for warning the driver of their presence in the immediate vicinity of this vehicle or of the road that he will soon have to take.
2. Description of the Related Art
Many devices have already been proposed for resolving this problem of assisting the driving of motor vehicles, adapted to poor visibility conditions and based on imaging systems comprising one or more cameras on board the vehicle.
For example, the documents U.S. Pat. Nos. 6,819,231 and 6,222,447 propose disposing one or more cameras at the rear or on the sides of a vehicle in order to offer the driver a view of the rear of the vehicle or of the space situated in what is usually called the blind spot, in order to assist the drive in his maneuvers, for example parking.
The document U.S. Pat. No. 6,473,001 for its part proposes disposing a camera at the end of an extensible arm at the front and/or at the rear of the vehicle. Under the control of the driver, the arm unfolds and thus moves the camera away from the front or rear of the vehicle, so that the camera, oriented perpendicular to the longitudinal axis of the vehicle, can laterally explore the scenes situated at each side of the front or rear of the vehicle, a screen in the cabin presenting these scenes to the driver. When the maneuvers of entering or leaving parking are ended and the driver stops the vehicle or begins to build up speed, the arm is refolded into the idle position in order to preserve it from impacts.
The document FR-A-2 859 860 proposes an obstacle-detection device comprising a stereoscopic imaging system, including two optical sensors integrated in the lighting or signaling means of the vehicle, the sensors being thus distant from each other by more than one meter and supplying information on the obstacle presented and on its distance in front of the vehicle.
The document FR-A-2 848 935 describes a method of detecting bends on a road, comprising a camera mounted in the vehicle, an image signal processing unit and a neural network, in order to display on a display screen the contours of the road situated in front of the vehicle.
In the same light, the document FR-A-2 847 367 proposes a device for determining the visibility distance in front of a vehicle, using a camera mounted in the vehicle, an image signal processing unit and a display screen for the results calculated by the device from the data collected.
It is thus known how to dispose a camera in a vehicle in order to transmit to the driver, with or without processing of the image signals, information and/or alerts on his immediate environment. However, these cameras are devolved to a given type of observation and fulfill only one function. In addition, they are for the majority of the time disposed behind the windscreen, for example level with the central rear view mirror, and thus occupy a not insignificant space in the field of vision of the driver.